Climate change: the potential for latitudinal effects on algal biomass in aquatic ecosystems

2003 ◽  
Vol 60 (6) ◽  
pp. 635-639 ◽  
Author(s):  
Kyla M Flanagan ◽  
Edward McCauley ◽  
Frederick Wrona ◽  
Terry Prowse

Arctic aquatic systems are considered to be highly susceptible to climate change. Both increases in temperature and nutrient input would be anticipated to alter primary production within these lakes. Consequently, understanding the current relationship between nutrients and productivity is crucial for predicting the effects of climate change. In this paper, we synthesize published data on algal biomass, total phosphorus, total nitrogen, maximum depth, altitude, longitude, and latitude to determine whether average algal biomass differs for temperate and arctic lakes. A total of 57 sources were used, resulting in data for 433 lake-years, ranging in latitudes from 41 to 79°N. Average algal biomass observed during the ice-free season increased significantly with phosphorous levels, but the latitude of the system had a significant negative impact on algal biomass. We briefly outline two major hypotheses, based on existing empirical evidence, for the lower algal yield found in higher latitude systems. The first hypothesis discusses bottom-up control and the influence of abiotic factors on algal biomass. The second hypothesis relates to food chain composition and top-down influences. The latitudinal effect on algal yield suggests that arctic lakes could dramatically increase in productivity if these systems experience increases in temperature and nutrient concentrations as predicted by climate change models.

1997 ◽  
Vol 48 (5) ◽  
pp. 445 ◽  
Author(s):  
A. I. Robertson ◽  
M. R. Healey ◽  
A. J. King

Two billabongs on the floodplain of the Murrumbidgee River, Australia, were partitioned in half with impermeable plastic barriers and the biomass of carp was manipulated to establish high- and low-carp biomass treatments in each billabong. Measurements of benthic variables (rates of particle settlement, biofilm development, sediment respiration, macrophyte detritus decomposition, sediment solid-phase nutrient concentrations and benthic algal biomass) were performed over four months from summer to winter 1995. Rates of particle settlement were greater in the high-carp treatment of each billabong throughout the experiment. High carp biomass had a negative impact on the autotrophic component of the biofilm developing on wood blocks placed at different heights above the sediment surface but the mechanism responsible differed between billabongs. Sediment oxygen demand became greater in the presence of a higher biomass of carp during the experiment but time courses differed between billabongs. Manipulations of carp biomass did not influence algal biomass on the sediment surface, the rate of decomposition of macrophyte detritus or sediment solid-phase nutrients or nutrient ratios. The impact of carp on benthic and surficial processes was significant but the mechanisms of change differed between billabongs.


Author(s):  
Mohamed El Amrani

Climate change is now an accepted reality. It is felt globally through increased temperature and precipitation regime disruption and increased frequency of extreme events such as floods and droughts. In the absence of effective mitigation and adaptation actions, these changes could have significant negative impact on the sustainability of agriculture and the resilience of populations especially in areas with fragile ecology. However, these changes remain an issue that is difficult to grasp and still not well integrated into management strategies at the farm, sector, and territory levels. The objectives of this research are to describe the production systems, and to study the resilience strategies, perception, and adaptive practices of farms in the Tleta watershed in Northwest Morocco in the face of climate change and landscape dynamics. It describes farming systems and activities, attempts to analyze how farmers perceive global changes in their landscape, and adopts innovative strategies and practices to adapt to them. It also shows that the actions of institutional actors in the area that can contribute to the resilience of the populations are numerous but remain fragmentary and lack integration.


2022 ◽  
pp. 1917-1931
Author(s):  
Mohamed El Amrani

Climate change is now an accepted reality. It is felt globally through increased temperature and precipitation regime disruption and increased frequency of extreme events such as floods and droughts. In the absence of effective mitigation and adaptation actions, these changes could have significant negative impact on the sustainability of agriculture and the resilience of populations especially in areas with fragile ecology. However, these changes remain an issue that is difficult to grasp and still not well integrated into management strategies at the farm, sector, and territory levels. The objectives of this research are to describe the production systems, and to study the resilience strategies, perception, and adaptive practices of farms in the Tleta watershed in Northwest Morocco in the face of climate change and landscape dynamics. It describes farming systems and activities, attempts to analyze how farmers perceive global changes in their landscape, and adopts innovative strategies and practices to adapt to them. It also shows that the actions of institutional actors in the area that can contribute to the resilience of the populations are numerous but remain fragmentary and lack integration.


2021 ◽  
Vol 14 (12) ◽  
pp. 597
Author(s):  
Yevheniia Antoniuk ◽  
Thomas Leirvik

The green bond market develops rapidly and aims to contribute to climate mitigation and adaptation significantly. Green bonds as any asset are subject to transition climate risk, namely, regulatory risk. This paper investigates the impact of unexpected political events on the risk and returns of green bonds and their correlation with other assets. We apply a traditional and regression-based event study and find that events related to climate change policy impact green bonds indices. Green bonds indices anticipated the 2015 Paris Agreement on climate change as a favorable event, whereas the 2016 US Presidential Election had a significant negative impact. The negative impact of the US withdrawal from the Paris agreement is more prominent for municipal but not corporate green bonds. All three events also have a similar effect on green bonds performance in the long term. The results imply that, despite the benefits of issuing green bonds, there are substantial risks that are difficult to hedge. This additional risk to green bonds might cause a time-varying premium for green bonds found in previous literature.


2021 ◽  
Author(s):  
Paola Ayala-Borda ◽  
Connie Lovejoy ◽  
Michael Power ◽  
Milla Rautio

Lakes and ponds are dominant components of Arctic landscapes and provide food and water for northern communities. In the Greiner Lake watershed, in Cambridge Bay (Nunavut, Canada), water bodies are small (84% < 5 ha) and shallow (99% <4 m). Such characteristics make them vulnerable to eutrophication as temperatures rise and nutrient concentrations from the greening landscape increase. Here, we investigated and compared 35 lakes and ponds in the Greiner watershed in August 2018 and 2019 to determine their current trophic states based on their chemical composition and phytoplankton communities. The ponds had higher trophic status than the lakes, but overall, most sites were oligotrophic. Lake ERA5, located upstream of any direct human influence was classified as eutrophic due to high total phosphorus (32.3 µg L<sup>-1</sup>) and a high proportion of Cyanobacteria (42.9% of total phytoplankton biovolume). Satellite imagery suggests the lake may have been eutrophic for the last 30 years. We hypothesize that the coupled effects of catchment characteristics and elevated local snow accumulation patterns promote higher nutrient leaching rates from the soils. We recommend further analysis and monitoring as eutrophication could become more widespread with ongoing climate change and the associated increases in temperature, precipitation, and catchment-lake coupling.


Author(s):  
Anouk Guyer ◽  
Cong van Doan ◽  
Corina Maurer ◽  
Ricardo A. R. Machado ◽  
Pierre Mateo ◽  
...  

AbstractHow climate change will modify belowground tritrophic interactions is poorly understood, despite their importance for agricultural productivity. Here, we manipulated the three major abiotic factors associated with climate change (atmospheric CO2, temperature, and soil moisture) and investigated their individual and joint effects on the interaction between maize, the banded cucumber beetle (Diabrotica balteata), and the entomopathogenic nematode (EPN) Heterorhabditis bacteriophora. Changes in individual abiotic parameters had a strong influence on plant biomass, leaf wilting, sugar concentrations, protein levels, and benzoxazinoid contents. Yet, when combined to simulate a predicted climate scenario (Representative Concentration Pathway 8.5, RCP 8.5), their effects mostly counter-balanced each other. Only the sharp negative impact of drought on leaf wilting was not fully compensated. In both current and predicted scenarios, root damage resulted in increased leaf wilting, reduced root biomass, and reconfigured the plant sugar metabolism. Single climatic variables modulated the herbivore performance and survival in an additive manner, although slight interactions were also observed. Increased temperature and CO2 levels both enhanced the performance of the insect, but elevated temperature also decreased its survival. Elevated temperatures and CO2 further directly impeded the EPN infectivity potential, while lower moisture levels improved it through plant- and/or herbivore-mediated changes. In the RCP 8.5 scenario, temperature and CO2 showed interactive effects on EPN infectivity, which was overall decreased by 40%. We conclude that root pest problems may worsen with climate change due to increased herbivore performance and reduced top-down control by biological control agents.


2020 ◽  
Author(s):  
Philip Boakye

The acceptance of electronic laboratory information system (LIS) is gradually increasing in developing countries. However, the issue of time effectiveness due to computerization is less clear as there is fewer accessible information. One of the key issues for laboratorians is their indecision with LISs’ would-be effect of time on their work. A polyclinic in Ghana was in the process of implementing electronic LIS. Several of the laboratorians did not have knowledge and skill in computing and there were disagreeing views on the time effectiveness of the LIS after implementation. The management of the polyclinic laboratory was concerned to assess time advantageousness of recording data when using the electronic LIS compared with paper-based LIS. <div><br></div><div>Five randomly selected laboratorians were provided two sheets of paper with tables to document the time they spent for both paper-based and electronic LIS. Data were collected for a total of 230 records,115 electronic LIS and 115 paper-based LIS. The t-test (mean-comparison test) was computed to compare the means of both electronic and paperbased LIS times. </div><div><br></div><div>There was a statistical significant difference in the time spent between electronic and paper-based LIS. The time spent between paper-based and electronic LIS was 0.41 minutes (95% CI 0.15 to 0.66) longer than in electronic LIS. </div><div><br></div><div>LIS can be adopted in polyclinics without having significant negative impact on time spent between electronic and paper-based LIS. More time–motion studies that include laboratorians are however necessary in order to get a more complete picture of time spent between electronic and paper-based LIS. </div>


Author(s):  
Ekaterina Maksimova ◽  
Ekaterina Maksimova ◽  
Vladimir Zhigulsky ◽  
Vladimir Zhigulsky ◽  
Vladimir Shuisky ◽  
...  

The macrophyte thicket ecosystems of higher aquatic vegetation in the Neva Bay (NB) and Eastern Gulf of Finland (EGoF) perform many important roles, including acting as the habitats, nesting sites and migration sites for aquatic and semi-aquatic birds, creating the specific conditions necessary for the spawning and growth of many species of fish, and taking part in the self-purification of the aquatic ecosystems. Many anthropogenic disturbances, hydraulic works in particular, have a significant negative impact on these macrophyte thicket ecosystems. In recent years, the active growth of a new type of macrophyte thicket has been observed in the NB. This is due to the aftereffects of the construction of the Saint Petersburg Flood Prevention Facility Complex (FPFC). It is quite likely that the total macrophyte thicket area in these waters is currently increasing. In the future, it will be necessary to assess the environmental impacts of the hydraulic works on the macrophyte thicket of the NB and EGoF, taking into account the background processes of the spatiotemporal dynamics of the reed beds in the waters in question. To do this, it will be necessary to carry out a comprehensive study of these ecosystems and identify patterns in their spatial and temporal dynamics. The program of the study has been developed and is currently being implemented by Eco-Express-Service, a St. Petersburg eco-design company.


2020 ◽  
Vol 26 (4) ◽  
pp. 397-406
Author(s):  
T. E. Chekanova

The presented study examines the problems of integration of the national banking systems of the member states of the Eurasian Economic Union (EAEU).Aim. The study aims to examine the major differences in various aspects of functioning of banking systems in the EAEU member states in terms of their impact on integration processes.Tasks. The author identifies the most prominent features of the banking systems of the EAEU states; reveals the depth of the existing differences through a comparative analysis of various indicators of national banking systems; outlines ways of overcoming integration problems associated with differences in the banking sectors of the Union states.Methods. This study is based on universal general scientific methods and elements of comparative, functional, and economic analysis within the framework of a systems approach. The author uses regulatory documents and banking reports of the EAEU states, statistical and analytical materials of the Eurasian Economic Commission (EEC), and data of Moody’s international rating agency.Results. The study identifies a number of aspects that contain the major differences in the functioning of banking systems in the EAEU member states; highlights the disproportions in the scale, level of development, financial stability, and risks of the banking spheres of the Union states; comparatively analyzes the proportion of banking and non-banking structures in the system and the share of the government and non-resident companies in the capital of banks; marks the difference in the pricing of banking services; determines differences in the existing approaches to banking regulation and the established standards; analyzes the major differences in the legislative acts of the central banks and governments of the EAEU member states and in the terms and definitions used. According to the results of the study, the major factors hindering the development of integration processes between the banking systems of the EAEU states are identified.Conclusions. The existing differences between the banking systems of the EAEU countries are diverse and multifaceted. The author states that the aspects addressed in this study have a significant negative impact on the further development of integration processes, describing the major directions and actions of the member states aimed at minimizing the exiting differences, which are required to facilitate the convergence of the states and the transition towards a common financial market.


Neurosurgery ◽  
2019 ◽  
Vol 86 (1) ◽  
pp. 132-138
Author(s):  
Christopher D Shank ◽  
Nicholas J Erickson ◽  
David W Miller ◽  
Brittany F Lindsey ◽  
Beverly C Walters

Abstract BACKGROUND Neurosciences intensive care units (NICUs) provide institutional centers for specialized care. Despite a demonstrable reduction in morbidity and mortality, NICUs may experience significant capacity strain with resulting supraoptimal utilization and diseconomies of scale. We present an implementation study in the recognition and management of capacity strain within a large NICU in the United States. Excessive resource demand in an NICU creates significant operational issues. OBJECTIVE To evaluate the efficacy of a Reserved Bed Pilot Program (RBPP), implemented to maximize economies of scale, to reduce transfer declines due to lack of capacity, and to increase transfer volume for the neurosciences service-line. METHODS Key performance indicators (KPIs) were created to evaluate RBPP efficacy with respect to primary (strategic) objectives. Operational KPIs were established to evaluate changes in operational throughput for the neurosciences and other service-lines. For each KPI, pilot-period data were compared to the previous fiscal year. RESULTS RBPP implementation resulted in a significant increase in accepted transfer volume to the neurosciences service-line (P = .02). Transfer declines due to capacity decreased significantly (P = .01). Unit utilization significantly improved across service-line units relative to theoretical optima (P &lt; .03). Care regionalization was achieved through a significant reduction in “off-service” patient placement (P = .01). Negative externalities were minimized, with no significant negative impact in the operational KPIs of other evaluated service-lines (P = .11). CONCLUSION Capacity strain is a significant issue for hospital units. Reducing capacity strain can increase unit efficiency, improve resource utilization, and augment service-line throughput. RBPP implementation resulted in a significant improvement in service-line operations, regional access to care, and resource efficiency, with minimal externalities at the institutional level.


Sign in / Sign up

Export Citation Format

Share Document